1. Field of the Invention
The present invention is directed generally to surface water drainage systems, in particular, a system that discharges surface water through an outfall to a body of water such as a river, lake or ocean.
2. Description of the Related Art
Water that collects on the surface of the land from rain or other sources will typically follow the path of least resistance until it reaches a local low point, usually a body of water such as a river, lake or ocean. If the path is steep, significant erosion of the land may occur. In developed areas, erosion is highly undesirable. Erosion can degrade support for buildings on the land, which may damage or destroy such buildings. Hence the owners of developed land usually want to take active steps to minimize erosion.
Water that collects on a surface behind a bluff presents a particular challenge in minimizing erosion. Some water may be absorbed into the ground and flow through the ground towards the local low point. However, if the ground is saturated or significantly paved, surface water will flow, usually towards and over the bluff. This can lead to significant erosion at the top and bottom of the bluff.
One traditional solution has been to route the surface water into a trough or pipe that extends over a lip of the bluff. This solution reduces the direct erosion on the bluff. However, it may increase erosion in front of the bluff, which may have the effect of undermining the bluff and eroding the bluff none the less. Another traditional solution is to route a pipe down the face of the bluff. This solution has a disadvantage in that it is difficult to secure the pipe to a bluff that is erosive. It has a further disadvantage in that it degrades the natural beauty of the bluff.